COMORBIDITY OF MIGRAINE AND EPILEPSY

In clinical practice, the finding of headache and epilepsy in the same patient and, moreover, in the presence of ictal and interictal epileptiform EEG patterns in patients with headache, is well known. These associations have stimulated research in the clinical and pathogenic relationships between headache and epilepsy Studies of the incidence of this association in epileptics and headache sufferers and an analysis of the link between the two different types of attacks have led several authors to support a non-casual clinical association between epilepsy and headache. So far, the pathophysiology of this condition remains unknown [1]. In adult patients, several studies demonstrated, according to IHS criteria, that the most common types of headache associated with epilepsy were migraine and tension-type. However, the rate of unclassified headaches has been remarkably high [2]. Probably, the most common relationship between seizures and migraine is when migraine-like headaches occur after seizures. Postictal headaches are often indistinguishable from migraine and are equally common in patients with or without a family history of migraine. Epileptiform abnormalities have been revealed in 9–13% of patients with migraine; this rate is significantly higher than expected from the normal population. Simple and complex partial seizures, primary and secondary generalized seizures, and tonic-clonic seizures have been reported associated with headache. It can be difficult to differentiate seizure disorders from migraine phenomena (and vice versa) in some patients. It is particularly a problem in children with atypical clinical presentations with or without abnormal EEGs [3]. In the absence of EEG recorded seizures, it is not uncommon to introduce an anticonvulsant if the history suggests a severe problem compatible with a diagnosis of epilepsy. Remission of the suspected events under anticonvulsant medication may indicate that the initial diagnosis of epilepsy was correct. However, there is evidence that in some patients, migraine phenomena also respond to these drugs. Valproate, gabapentin, topiramate, and tiagabine have been demonstrated to be efficacious. Furthermore, epileptic patients with a history suggesting migraine require a combination of both antiepileptic and antimigraine drugs in order to achieve full control of epilepsy